1. Field of the Invention
The present invention relates to a data processing apparatus in which data is reproduced from a non-linear accessible recording medium having recorded thereon both high rate data and low rate data for the same material. This application claims priority of Japanese Patent Application No.2002-006402, filed on Jan. 15, 2002, the entirety of which is incorporated by reference herein.
2. Description of Related Art
In high-speed reproduction of a picture recorded on a non-linear accessible recording medium, such as optical discs, magnetic discs or a semiconductor memories, it is customary to reproduce frame-skipped pictures. Thus, in reproducing at a 50-tupled speed, pictures are updated every 50 frames, such that 49 frames in-between are skipped. For example, if pictures are recorded by a compression system employing correlation along time axis, such as MPEG2 (Moving Picture Experts Group-2), it occurs from time to time that the information on the forward side GOP (Group of Picture) and on the rear side GOP is required for decoding. The result is that limitations by the decoder processing speed are imposed on the number of frames that can be decoded at the time of high speed reproduction such that the frame-skipping interval is not constant instantaneously and hence the reproduced picture is jerky for the same skipping rate.
In case of high-speed reproduction on the aforementioned non-linear recording medium, non-jerky reproduced pictures, such as those obtained on high-speed reproduction of the conventional analog VTR, for example, are desired. This, however, has been difficult in case the pictures have been compressed in accordance with a compression system employing the correlation along time axis such as that described above.
On the other hand, in high-speed reproduction of the analog video information, the audio information related to the video information is also reproduced at a high speed, such that speech-based scene retrieval is also possible. In high-speed reproduction of the audio information recorded on the non-linear recording medium, however, reproduced audio data tends to be discrete or to become constant in the sound interval irrespective of the reproducing speed in a manner distinct from the case where the audio signals are recorded on a longitudinal track with high frequency bias recording as in the case of analog VTR.